Anthropic, a US artificial intelligence company, has accused Chinese technology and e-commerce giant Alibaba of illicitly extracting capabilities from its Claude AI model in what it describes as the largest known attack of its kind on the company, according to a letter seen by Reuters.
Massive Distillation Campaign Uncovered
Anthropic stated that the campaign, which it terms a "distillation" effort, involved training a less capable model on the outputs of a stronger one. The attack allegedly took place between April 22 and June 5, 2026, generating more than 28.8 million exchanges with Claude through almost 25,000 fraudulent accounts. In the letter, Anthropic claimed that distillation is a method to help accelerate China's ability to reach Anthropic's advanced Mythos Preview capabilities. The company said the operation was conducted by operators affiliated with Alibaba and Alibaba Qwen, Alibaba's AI lab.
Alibaba's Silence and US Government Involvement
Alibaba did not immediately respond to a request for comment. The letter, dated June 10, was sent to Senators Tim Scott and Elizabeth Warren, the chair and ranking member of the US Senate Banking Committee, ahead of a scheduled hearing on AI. In April, the White House accused China of stealing US AI labs' intellectual property on an industrial scale. Anthropic expressed support for the US government's efforts to combat such attacks, including partnering with private sector AI companies through threat-intelligence sharing and other exercises.
Previous Incidents and Growing Sophistication
In a February posting, Anthropic had identified a campaign by Chinese AI startup DeepSeek—whose low-cost AI model sent shockwaves through the technology world in January 2025—and two other Chinese AI labs to illicitly extract capabilities from its Claude AI platform. DeepSeek's operation involved over 150,000 exchanges, while Moonshot AI had over 3.4 million exchanges and MiniMax over 13 million. Anthropic noted at the time that the campaigns were growing in "intensity and sophistication" and that addressing the threat would require "rapid, coordinated action among industry players, policymakers and the global AI community."
Pentagon Listing and Commerce Department Actions
Alibaba was added to the Pentagon's Chinese military companies list this month, a designation it is challenging. However, the Commerce Department has held off placing DeepSeek on a trade blacklist, as Reuters exclusively reported this month, despite it being deemed a national security risk by an interagency governmental committee, as the department tries to avoid escalating tensions with Beijing. On June 12, two days after Anthropic sent the letter, the Commerce Department imposed controversial restrictions on Anthropic's latest Mythos and Fable AI models because officials feared they could be deployed by military intelligence users in China and other countries of concern. The restrictions resulted in Anthropic disabling access to the models globally.
